Starch fixation and retention in recycled fiber systems
The present invention provides a novel method and composition for enhancing the efficiency of starch adsorption (i.e., starch trapping) from starch-containing furnishes comprising high content of recycled fibers for use in paper making processes such as pulp, paper, or board production. A novel polymer coagulation system is disclosed in which two quick inversion cationic emulsion polymers (starch trapping polymers A and B) are co-mixed at optimal blend ratios to meet specific recycled fiber and process water requirements for different recycled fiber plants and added to furnishes prior to formation of paper or board in a paper machine. Co-mixed solutions of starch trapping polymers A and B provide synergistic enhancements in (i) starch trapping efficiency and (ii) starch retention in the produced paper or board over equivalent dosage levels of singly administered polymer A, polymer B, or conventional starch trapping products, without over-flocculation or formation of stickies.
1 . A composition comprising a combination of quick inversion cationic emulsion starch trapping polymers comprising:
a. starch trapping polymer A having polymer standard viscosity of between 3 to 3.5 cPs, when measured by a Brookfield viscometer with UL adapter at 25° C. on a 0.1% by weight polymer solution in 1 M NaCl, and 15-23 mol % cationic monomer content, and
b. starch trapping polymer B having polymer standard viscosity of between 1.5 to 2.0 cPs, when measured by a Brookfield viscometer with UL adapter at 25° C. on a 0.1% by weight polymer solution in 1 M NaCl, and 25-45 mol % cationic monomer content.
2 . The composition of claim 1 , wherein said polymers A and B are quick inversion reverse phase cationic emulsion polymers and are optionally obtained by reverse phase emulsion polymerization of a monomer blend comprising non-ionic monomers, 15-50 mol % cationic monomers, optionally at most 50 ppm of a crosslinking agent, and further optionally ranges from 2-30 ppm and a chain transfer agent.
3 . The composition of claim 2 , wherein the nonionic monomers comprise one or more of acrylamide, methacrylamide, N-alkyl acrylamides, N-methylacrylamide, N,N-dialkylacrylamides, N,N-dimethylacrylamide, methyl acrylate, methyl methacrylate, acrylonitrile; N-vinylmethylacetamide or formamide, N-vinyl acetate and vinyl pyrrolidone.
4 . The composition of claim 3 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
5 . The composition of claim 2 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
6 . The composition of claim 1 , wherein said starch trapping polymer A comprises 19-21 mol % cationic monomer content and starch trapping polymer B comprises 30-40 mol % cationic monomer content.
7 . The composition of claim 1 , wherein said cationic monomers comprise one or more of diallyldimethylammonium chloride (DADMAC), acryloyloxyethyltrimethylammonium chloride, methacrylates of N,N-dialkylaminoalkyl compounds and quaternaries and salts thereof, N,N-dimethylaminoethylacrylate methyl-chloride salt, monomers of N,N-dialkylaminoalkyl (meth)acrylamides and salts and quaternaries thereof, N,N-dialkylaminoethylacrylamides, methacrylamidopropyltrimethylammonium chloride, and 1-methacryloyl-4-methyl piperazine.
8 . The composition of claim 7 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
9 . The composition of claim 1 , wherein said starch trapping polymer A is a quick inversion cationic emulsion polymer co-polyacrylamide comprising cationic quaternary amine side chains and/or said starch trapping polymer B is a quick inversion cationic emulsion polymer co-polyacrylamide comprising cationic quaternary amine side chains.
10 . The composition of claim 9 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
11 . The composition of claim 1 , wherein the ratio of polymer A/polymer B ranges from 90/10 to 50/50.
12 . The composition of claim 11 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
13 . The composition of claim 1 , wherein the ratio of polymer A/polymer B ranges from 80/20 to 60/40.
14 . The composition of claim 13 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
15 . The composition of claim 1 , wherein the ratio of polymer A/polymer B is 70/30.
16 . The composition of claim 1 , wherein the ratio of polymer A/polymer B ranges from 10/90 to 1/99.
17 . The composition of claim 1 , wherein the ratio of polymer A/polymer B is no more than 1/99.
18 . The composition of claim 1 , which further comprises or is comprised in a starch comprising composition, wherein said starch comprising composition optionally comprises one or more of (i) starch comprising fiber stock, optionally recycled fiber stock, (ii) starch comprising mill broke fibers, and (iii) starch-containing process water.
19 . The composition of claim 1 , wherein the cationic monomer content of Polymer A ranges from 17-22 mol %.
20 . The composition of claim 1 , wherein the cationic monomer content of Polymer A ranges from 19-21 mol %.
21 . The composition of claim 1 , wherein the cationic monomer content of Polymer A is 20 mol %.
22 . The composition of claim 1 , wherein the cationic monomer content of Polymer B ranges from 28-42 mol %.
23 . The composition of claim 1 , wherein the cationic monomer content of Polymer B ranges from 30-40 mol %.